It is often desirable to provide the surface of an object with a polymeric coating to protect the surface or to provide the surface with properties of the polymer coating. For example, various paint-like coating compositions are employed to provide the surfaces of metals, wood and the like with thin, protective polymeric films.
The adhesion of polymeric films such as those described above to the surfaces to which they are applied are commonly largely mechanical. The surfaces often are roughened or otherwise prepared before a polymeric coating is applied so as to increase the degree of mechanical adhesion. Polymers are generally not chemically bonded to the surfaces upon which they are applied, and polymer coatings generally have not been used as coatings for devices which may be implanted in the human body or to devices which come into contact with body fluids during use, such as contact lenses. Coatings for objects such as these should adhere tenaciously to their surfaces even in the presence of body fluids and other liquids.
To improve the adhesion of certain polymer species to supporting surfaces, U.S. Pat. Nos. 4,663,232, 4,311,573, 4,595,632 and 4,589,964 teach that surfaces to be coated must be carefully prepared, as by precoating, using careful, often time-consuming procedures to receive polymer species.